1. Field of the Invention
The present invention relates generally to an antenna, and more particularly to a multi-band antenna used in a portable electronic device.
2. Description of the Prior Art
With the development of wireless communication, more and more portable electronic devices, such as a notebook, install an antenna system for working in a Wireless Local-area Network (WLAN). Transmitting and receiving signals plays an important role in wireless communication process. In recent years, a majority of WLAN bases on Bluetooth technical standard or 802.11 technical standard. Antenna in Bluetooth technical standard is based on 2.4 GHz frequency band, and in 802.11 technical standard is based on 2.4 GHz and 5 GHz. So, antenna in notebook mostly works at the above frequency bands at the present time.
However, an antenna used in a notebook is limited by the inner space of the notebook. So, the size of the antenna must be designed to be suitable for the inner space of the notebook. Most conventional antennas having big structure go against miniaturization development of portable electrical device.
For example, U.S. Pat. No. 6,861,986 B2 discloses a PIFA (Planar Inverted-F Antenna) capable of working on two different frequency bands. The PIFA antenna comprises a conductive radiating element 3 in the form of a wire that extends in a longitudinal direction and that has opposite first and second ends 31, 32. So, the PIFA antenna occupying big space in longitudinal direction goes against miniaturization development of portable electrical device.
Hence, in this art, a multi-band antenna to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiment.